1. Field of the Invention
The invention relates to a twin-rotor helicopter, more particularly to a transmission device for a twin-rotor helicopter.
2. Description of the Related Art
A conventional twin-rotor helicopter includes an upper rotor assembly and a lower rotor assembly that rotate in opposite directions. A transmission mechanism is used to transmit power from a helicopter engine to drive rotation of the rotor assemblies in the opposite directions. However, the conventional transmission mechanism usually has a very complicated structure and is expensive to fabricate.